Shader "GJ/MoveTrail" {
    Properties {
        _MainTex ("Texture", 2D) = "white" {}
        _Color ("Color", Color) = (1,1,1,1)
        _Fade ("Fade", Range(0, 1)) = 0.9
    }
    SubShader {
        Tags {
            "Queue"="Transparent"
            "RenderType"="Transparent"
        }
        Cull Off Lighting Off ZWrite Off
        Blend SrcAlpha OneMinusSrcAlpha
        Pass {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
 
            #include "UnityCG.cginc"
 
            struct appdata {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };
 
            struct v2f {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };
 
            sampler2D _MainTex;
            float4 _MainTex_ST;
            fixed4 _Color;
            fixed _Fade;
 
            v2f vert (appdata v) {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }
 
            fixed4 frag (v2f i) : SV_Target {
                fixed4 tex = tex2D(_MainTex, i.uv);
                tex.a = tex.a > 0 ? _Fade : 0;
                return tex;
            }
            ENDCG
        }
    }
}